. If the center is completely and exclusively
disturbed, then it is a case of pure ataxic aphasia. Spontaneous
speaking, saying over of words said by another, and reading aloud of
writing, are impossible. (Kussmaul.) On the other hand, words heard are
understood, although the concepts belonging with them can not be
expressed aloud. The verbal memory remains; and the patient can still
express his thoughts in writing and can copy in writing what he reads or
what is dictated to him.

(3) Periphero-Expressive or Articulatory Disturbances.

The centrifugal paths from the motor speech-center to the motor nerves
of speech and to their extremities, or else these nerves themselves,
are injured. Then occurs _dysarthria_, and, if the path is totally
impassable at any place, _anarthria_. The hearing and understanding of
words are not hindered, but speaking, repeating the words of others,
and reading aloud are, as in the last case (2, _c_), impossible. In
general this form can not be distinguished from the foregoing when
both are developed in an extreme degree, except in cases of peripheral
dysarthria, i. e., dyslalia, since, as may be easily understood, it
makes no difference in the resulting phenomena whether the motor
center itself is extirpated or its connections with the motor outlet
are absolutely cut off just where the latter begins; but if this
latter is injured nearer to the periphery, e. g., if the hypoglossus
is paralyzed, then the phenomena are different (paralalia, mogilalia).
Here belongs all so-called mechanical dyslalia, caused by defects of
the peripheral speech-apparatus.

Of these five forms each occurs generally only in connection with
another; for this reason the topical diagnosis also is often
extraordinarily difficult. But enough cases have been accurately
observed and collected to put it almost beyond a doubt that each form
may also appear for a short time purely by itself. To be sure, the
anatomical localization of the impressive and expressive paths is not
yet ascertained, so that for the present the centripetal roads from
the acusticus to the motor speech-center, and the intercentral fibers
that run to the higher centers, are as much unknown as the centrifugal
paths leading from them to the nuclei of the hypoglossus; but that the
speech-center discovered by Broca is situated in the posterior portion
of the third frontal convolution (in right-handed men on the left, in
left-handed on the right) is univer